Integrity protection of untrusted storage
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Helsinki University of Technology |
Diplomityö
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Date
2007
Department
Major/Subject
Informaatiotekniikka
Mcode
T-115
Degree programme
Language
en
Pages
(9) + 54
Series
Abstract
Storing information such as data backups or family pictures on third party servers instead of local storage can be conceived as getting increasingly commonplace as more and more providers are starting to offer these services. In this situation, a user may not fully trust the external storage space and may want to verify the integrity of the stored data when it is retrieved, using a small authentication value on local trusted storage. Several cryptographic integrity protection schemes exist for computing the authentication value, the most commonly used being Merkle hash trees. These hash trees incur logarithmic work (in the total number of blocks) for updating and for verifying a block, and a linear amount of additional untrusted storage space. There are also alternative methods such as incremental hashing and dynamic accumulators, where the work required for one operation is constant (updating for incremental hashing, verifying for accumulators), whereas the other operation incurs linear overhead. This project consisted of implementing an integrity checker using incremental hashing and dynamic accumulators, and evaluating the performance of both schemes. The integrity checker was also integrated into an integrity protected file system using the open source project FUSE for implementing file systems in userspace under Linux. The implementation language was Java, and the FUSE integration was done using the FUSE-J Java bindings. This Master's Thesis has been done for IBM Zürich Research Laboratory, Switzerland.Description
Supervisor
Simula, Olli|Molva, RefikThesis advisor
Cachin, ChristianKeywords
integrity, integritet, hashing, hashing, incremental hashing, inkremental hashing, dynamic accumulator, dynamisk ackumululator, FUSE, Java